Conservative Treatment for Atlantoaxial Dislocation Patients Without Neurological Deficit

Inclusion Criteria: * The patients meet the diagnostic criteria for atlantoaxial dislocation, that is, the ADI exceeds the normal range: it is over 3 mm in adults and over 5 mm in children. * The patients have no clinical manifestations of the nervous system, including occipital neuralgia, manifestations of cranial nerve impairment (such as dysphagia, dysarthria, nystagmus, etc.) and manifestations of spinal cord impairment (such as unsteadiness in holding objects, unsteady gait, decreased limb muscle strength, etc.). * After fully understanding their own conditions as well as the advantages, disadvantages and risks of both conservative treatment and surgical treatment, the patients can choose the initial treatment method on their own. If they choose conservative treatment, they will be included in the conservative treatment. If they choose surgical treatment, they will be included in the surgical intervention group. Exclusion Criteria: * Patients who have undergone surgeries in the cranio-cervical junction previously. * Patients with infections or tumors in the cranio-cervical junction. * Patients with fresh fractures in the cranio-cervical junction. * Patients with clinical manifestations of nerve deficit. * Patients with severe diseases in other spinal regions such as the thoracic and lumbar spine that affect their clinical symptoms; patients with motor neuron diseases like amyotrophic lateral sclerosis and other severe neurological diseases. * Patients who have partici…